DE3818600A1 - Process and device in a paper machine cylinder-dryer in which a two-fabric path is used - Google Patents

Process and device in a paper machine cylinder-dryer in which a two-fabric path is used

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Publication number
DE3818600A1
DE3818600A1 DE19883818600 DE3818600A DE3818600A1 DE 3818600 A1 DE3818600 A1 DE 3818600A1 DE 19883818600 DE19883818600 DE 19883818600 DE 3818600 A DE3818600 A DE 3818600A DE 3818600 A1 DE3818600 A1 DE 3818600A1
Authority
DE
Germany
Prior art keywords
drying
web
cylinder
nozzle
fabric
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
DE19883818600
Other languages
German (de)
Other versions
DE3818600C2 (en
Inventor
Pekka Dipl Ing Eskelinen
Hannu Kokkala
Raimo Virta
Vesa Vuorinen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Valmet Oy
Original Assignee
Valmet Paper Machinery Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to FI872691A priority Critical patent/FI80103C/en
Application filed by Valmet Paper Machinery Inc filed Critical Valmet Paper Machinery Inc
Publication of DE3818600A1 publication Critical patent/DE3818600A1/en
Application granted granted Critical
Publication of DE3818600C2 publication Critical patent/DE3818600C2/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21FPAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F5/00Dryer section of machines for making continuous webs of paper
    • D21F5/02Drying on cylinders
    • D21F5/04Drying on cylinders on two or more drying cylinders
    • D21F5/042Drying on cylinders on two or more drying cylinders in combination with suction or blowing devices

Abstract

Process in a paper machine cylinder-dryer in which the web is guided by using an upper fabric (40) on the upper cylinders and a lower fabric (30) on the lower cylinders. The fabrics (30, 40) are guided by the surface of the drying cylinders and by guide rolls (34, 35, 44) arranged in their interspaces in such a way that the web (W) has direct drying contact with the surface of the upper cylinders (41, 42) in the upper row of cylinders by means of being pressed on by the upper fabric (40), and is pressed against the surface of the lower cylinders (31, 32) by the lower fabric (30). As the web (W) and the drying fabric (30, 40) leave the drying cylinder (31, 41), the web (W) is sucked firmly on to the drying fabric (30, 40) by sucking through the drying fabric (30, 40) in a low-pressure region (A-, N-) arranged at the relevant position of the drying fabric draw in such a way that the length of the free draw (Wp) of the web is significantly shortened. The said low-pressure region (A-, N-) is generated by means of an air-blast which is blown through a passage (R) bounded by the outer surface of the fabric (30, 40) on the drying cylinder (31, 32, 41, 42) and a wall surface (14) and elongated (L) in the blast direction. By means of the relevant passage (R), the boundary-layer flow following the drying fabric (30, 40) is directed in the opposite direction with respect to the draw of the fabric (30, 40) and, in the spaces available on the back of the said passage (R), a... Original abstract incomplete. <IMAGE>

Description

The invention relates to a method in a paper machine cylinder dryer in which the web is used an upper sieve on the upper cylinders and a lower sieve is guided on the lower cylinders, the sieves of the Surface of the drying cylinders and in between arranged guide rollers are guided such that the web on the top cylinder row by pressing the top sieve direct drying contact with the surface of the upper cylinder which has and accordingly from the bottom sieve against the surface che the lower cylinder is pressed, and the web in the ver drive from one to the other row of cylinders on certain Route is run in free train, and the train in this Process while web and dryer fabric the drying cylinder leave, with suction through the dryer in one the relevant point of the dryer fabric arranged Vacuum area is sucked firmly onto the dryer fabric art that the length of the free train of the train is essential shortened, and the suction effect by blowing at least one or more with respect to the running direction of this Place the dryer fabric in the opposite direction directional air jet or jets is achieved, who eject air from the rooms behind, whereby the said negative pressure area is generated.  

The invention also relates to a device for a paper machine multi-cylinder dryer, in the two-cloth guidance is applied, and the device is provided in the spaces between adjacent drying cylinders to be arranged, which gaps from those over the adjacent drying cylinders running drying ben and the free sectors of these leading guide rollers be limited, the device from a blow box consists of the entire width of the dryer fabric extends, and the blow box at least one nozzle gap has arranged and aligned so that a blow with respect to the movement from the nozzle gap mentioned direction of the dry running past this point has it directed in the opposite direction.

Under the guidance of a sieve, a Understanding the web guide, in which the web via heated Troc Kenzylinder is guided, the web from the dryer fabric supported from one row of cylinders to another, that the path in one row of cylinders between the Dryer screen and the cylinder surface is located in the other row of cylinders is outside and the dryer fabric between the cylinder surface and the drying cloth and the Train traverses the trains between the rows of cylinders by it is supported by the dryer fabric. The advantage of this one cloth guidance consists in the fact that the web is from Dryer screen is supported and none or at least none has much long free moves, with which the risk of ver wrinkling and tearing of the web is reduced.

Under a two-wire guide is in the present Registration a known type of train support and -understanding on heated drying cylinders at which an upper sieve on the upper cylinders and a lower cylinder on the lower cylinders a sub-sieve is used that comes from the surface of the Troc  kenzylinder and Leit arranged in between Roll is performed such that the web on the top cylinder row from the top sieve in direct drying contact with the Surface of the upper cylinder and accordingly from the lower sieve is pressed against the surface of the lower cylinder.

The present invention expressly relates to the two-wire guide.

In the two-wire system, the train has when running from one row of cylinders to another is generally essential had long free trains. These free moves are against flat and the resulting tearing and wrinkling vulnerable, which disadvantage in a particularly increased form in Initial part of the dryer section occurred where the web is still relatively wet and therefore weak and its elastic Properties favor the flutter.

This disadvantage was tried at the time Shortening of the free trains mentioned above in the beginning the dryer section by eliminating the through the axes of the upper and lower cylinder rows Arranged layers with a shorter distance from each other than you were used to this before or like this, for example would have been optimal in terms of drying performance.

The 3rd and 4th dryer groups were also run on a single screen retrofitted, which was an emergency solution because this Reduction of the evaporation capacity and to make it more difficult Carrying out ventilation.

The flutter of the paper web in a drying group Two-wire routing was attempted by moving the felt guide Reduce rolls so that the paper web only over one Shorter distances need to run unsupported. In the U.S. patent  No. 37 53 298 a drying group of this type is described. According to the journal article "Engineering consideration for lightweight paper drying in high speed machines "(Paper Tech nology and Industry July / August 1978) was the roller arrangement solution according to US patent 37 53 298 in a Swedish paper machine applied with a speed of 853 m / min has been reached. But Schwie continued to occur due to the flutter of the web.

The flutter of the paper web has been published chung "Paperin valmistus", translated "paper manufacture", (Teaching and Handbook III Part I of the Association of Paper Engineers of Finland) on pages 699-700 where it is found that the flutter of the web edges in space mean is not caused by air currents like this is often accepted. This allows the web to flutter not by directing the air flows in the dryer section prevent significantly, which has often been tried.

According to the current view, the web flutter is at all due to too strong internal currents of the named Pockets and existing pressure differences in both the pockets as well as in the ge of web and screen and cylinder surfaces formed columns. The strong air mentioned flows and generated pressure differences are consequences of Boundary layer currents from sieves, trains and cylinders surfaces are induced during their movement.

The free trains mentioned above, free cylinders surfaces and the screens or felts guided by guide rollers limit pockets inside the multi-cylinder dryer that are open at their end faces, and ventilation this Bags is considered an important factor for performance and Uniformity (moisture profile) of drying the Multi-cylinder dryer viewed.  

The machine speeds of paper machines are has risen steadily in recent years and is approaching today already the 1500 m / min limit. The flapping of the web forms doing so is a growing problem affecting the running characteristics of the Paper machine affected. The flyover from the press section to the dryer section and the support of the web in the area of the sieve guide is with process and device in previous FI patents and FI patent applications are described by the applicant, but in Area of two-wire guidance, especially in the 3rd and 4th Operating group, are difficulties at high speed applied.

With the previously known methods and devices however, the aim is not to put in the mentioned pockets to influence pumping air quantities in such a way that the The web coming from the cylinder is sucked onto the dryer fabric.

In the known two-wire guides is in the Pocket pumping amount of air essentially from the machine speed, the geometry of the transport part and the Permeability of the dryer fabric dependent.

The moisture profile of the bags in question was carried out in a manner known per se such that the in the Bags of existing blowguns in the transverse direction of the machine Segments are divided, which are for the purpose of regulating the Open and close the bag to blow air. Reference Lich this solution is based on the FI patent 68 278 Applicant pointed out.

With the two-wire guide, one is created on the wire wet boundary layer while the sieve over the cylinder runs, the water vapor evaporating from the paper diffuses through the sieve. When removing the sieve  this moist boundary layer passes from the cylinder through the sieve into the pocket due to the prevailing in the gap Negative pressure. With the previously known pocket ventilation could not destroy the above-mentioned boundary layer will. The present invention has for its object Solve a problem.

In FI application No. 8 53 525 (corresponding to DE-OS 36 30 570) the task was a method and an apparatus to create with which the web flutter on the above free moves can be significantly reduced and thus the Risk of tearing and stretching of the web are reduced. Except In the aforementioned application, the task was to Method and device for ventilation of the concerned Bags and to master the moisture profile in To create the cross direction of the web. For the tasks mentioned was in the inventive method of FI registration as re-viewed that the web after it and the dryer fabric have left the drying cylinder in one of the in question coming point of the dryer fabric induced sub pressure area through a through the dryer fabric following suction is firmly sucked onto the dryer fabric in such a way that the length of the free train of the web ver shortens, and that the above-mentioned suction by blowing with respect to the running direction of the located at this point Dryer fabric and the wire guide located at this point roll the air jet in opposite directions len is generated from the rooms behind them Eject air, creating the affected vacuum areas be generated.

In the device of the FI application was for new seen that it consists of a blow box that overlaps the entire width of the drying wire extends that in the mentioned blow box are at least two nozzle gaps,  which are arranged and aligned in such a way that different blows in the opposite direction to the direction of the coming of the first nozzle gap Dryer fabric and in the opposite direction to the movement direction of coming to the second nozzle gap Let the free surface of the wire guide be adjusted.

Because the web thanks to the invention of the application mentioned does not run directly to the next drying cylinder, but the Dryer to the guide roller, essentially up to it Horizontal central axis follows, becomes much shorter free unsupported train of the train reached and the run there stabilized by. In addition, with the invention Unstability of the web run in the exit gap between Troc cylinder and dryer are eliminated where on both sides There is uncontrolled negative pressure on the web, which is known in the art Devices has caused web flutter. Thanks to the invention according to FI registration 8 53 525 the pumping into the pocket Air volume by controlling the Bla with the invention Solutions achieved negative pressure can be controlled. That briskness The easiest way to do this is to regulate the blow box pressure. Said regulation can be independent of the permeabi of the dryer fabric.

The procedure and the device after FI registration 8 53 525 are advantageously realized in such a way that with the same device the amount of air coming out of the bag and their distribution in the transverse direction is affected, what in turn affects the moisture profile of the web. This is done by executing one or more references Lich the opposite direction of air bubbles that expediently from the same blow box with which the vacuum areas acting according to the invention are generated, on the pull of the dryer with which the screen from the guide roller returns to the drying cylinder on the web. With ge  called air blowing creates negative pressure, which by Air flow pumping out of the bag through the sieve decreased. The web is moisture-profiled by the arrangement mentioned on the outlet side of the Troc kensiebes such that a by opening the blow segment web humidifying effect arises because the air does not come from the Bag is pumped out. When the blow segment closed is subordinate to the path passing by at this point a drying effect because the air is at this point pump out of his pocket. So that the mastery of the Moisture profile just reversed, as with the known pocket ventilation process.

An advantage of the invention of the above-mentioned FI application 8 53 525 is further that the method enables the use of very open dryer fabrics, ie screens with a high permeability, such that open dryer fabrics can be used, the permeability of which, for example, in the range 10,000- 15,000 m 3 / m 2 × h, whereas the permeability of the screens previously used in two-wire guides is in the range 1500-2000 m 3 / m 2 × h. Thanks to the more open dryer fabrics than before, the evaporation on the cylinder through the screen is increased, which in turn leads to a decrease in the average moisture level. The ventilation through the outlet gaps between the cylinder and dryer fabric also increases thanks to open screens.

The present invention has the task of the method ren and the device of the said FI application Maintaining their beneficial properties further develop in such a way that the ventilation of the web is effective and the running properties of the paper machine in the area of Two-wire guidance can be improved. To the devices of the present invention will have higher requirements than before  posed because the efforts are constantly going to the Increase machine speeds.

In particular, the object of the invention is to provide a method and an apparatus in which the Vacuum level on the inlet sides of the sieves from the Zylin up to the guide roll with the method according to the invention and the device raised significantly more than before and thus the web run can be improved.

Associated with the invention is appropriate, however not necessarily, one on the sieve exit side of the train pockets placed between the guide roller and drying cylinder ventilation arrangement, which advantageously divided into segments can be used to control the moisture profile to the machine and to dry out the edge zones too much to prevent the web.

To achieve the above and clear below becoming goals for the method of the invention in we considerable characteristic that the mentioned negative pressure area with a blow created by one of the outer surface of the screen on the drying cylinder and a wall surface limited, elongated in the blowing direction Passage is blown, and that with the said enough long passage the boundary layer following the dryer fabric flow essentially total with respect to the wire draw is directed in the opposite direction and in the rear of the above-mentioned passage is sufficient for existing rooms the vacuum level is isolated.

For the device according to the invention is in turn essential characteristic that behind the nozzle, purpose moderate Coanda nozzle, in the blowing direction behind the nozzle one Wall of the blow box is attached, which together with the  Outer surface of the drying cylinder surface in the area of Sieve located on the wall delimits an elongated passage, whose length is several times greater than the width of the Culvert, i.e. than the distance from the outer surface of the Sieben up to the wall surface of the blow box.

According to the invention on the traction of the lower and upper sieve between drying cylinder and wire guide roller outside of it Loop a relatively long counterflow blow passage used, its length so long and its width so small is chosen that this on the outer surface of the sieve following boundary layer flow essentially the other way round with the help of the counterflow of the said passage in the opposite direction, and thus pumping through the sieve in the direction of the gap between the sieve and its Guide roller is effectively prevented.

According to the invention, the length of the counter is flow blower passages generally in the range 100-500 mm, expedient in the range of approx. 250-350 mm, and the passage width, i.e. the distance between the passage limiting bo gene-shaped wall of the blow box and that on the cylinder located sieve, generally in the range 20-100 mm, expedient in the range of approx. 40-70 mm. In the invention can the latter distance can be chosen what the assembly the device relieved because of sufficient security distances can be achieved.

With the method and the device according to the invention is on the screen inlet side in the gap between guide roller and Sieve a larger vacuum than previously available, its Pressure level can reach a size of up to approx. -100 Pa.

In an advantageous embodiment of the invention can be in the entry gaps between the seven and their  Guide rollers can be achieved using vacuum just a nozzle and seal assembly. So that The amount of air to be injected can be significantly reduced.

In general, for security reasons, a minimum distance of 50 mm between the blow box and the moving sieving surface required. This distance is thanks to the Er finding can be realized without difficulty. Still can with With the help of the invention, the vacuum level of the inlet gap between sieve and guide roller increased more than before the.

In the following the invention with reference to a ge shown in the figures of the accompanying drawing Exemplary embodiments, on the details of which the invention but not limited, is described in detail.

Fig. 1 shows a cylinder dryer using the method and the device according to the invention seen from the operating side.

FIG. 2 shows the blow box according to FIG. 1 viewed schematically from the direction B entered in FIG. 1.

Fig. 3 shows a cross section of a first embodiment of the invention in which two blowing nozzles and pocket ventilation are used.

FIG. 4 shows a cross section of an embodiment of the invention in which a blowing nozzle and instead of the second blowing nozzle a sealing arrangement and a pocket ventilation nozzle arrangement are used.

Fig. 5 shows in the manner of FIGS . 3 and 4, an embodiment of the invention, in which two blow nozzles but no pocket ventilation nozzles arrangement are used at all.

Fig. 6 shows, corresponding to Fig. 5, an embodiment of the invention, in which only one blowing nozzle but no pocket ventilation nozzle is used at all.

According to Fig. 1, the multi-cylinder dryer in which the invention is applied, for a number lower cylinders 31 and 32, etc., and a corresponding set top cylinders 41 and 42, etc. The dryer consists of a bottom wire 30, of in the interstices of the lower cylinder 31 , 32 , 33 arranged guide rollers 34 and 35 is guided. Accordingly, there is an upper sieve 40 on the upper cylinder row, which is guided by guide rollers 44 , etc. This is a so-called two-wire guide, in which the paper web W rests on the upper and lower cylinders, it being located under the drying wire 30 , 40 . The web W has free trains W p between the rows of cylinders, which were generally sensitive to flutter. On the other hand, there is significant evaporation of water from the web W on these free trains W p . The stand structures of the dryer section are known per se and are not shown here.

According to Fig. 1 to 6 in the spaces between the upper cylinders and the lower cylinders 10 of the invention blow boxes mounted, extending in transverse direction over the entire width of the web W and the drying wires 30 to 40. The blow boxes 10 consist of vertical walls 14 and 16 and horizontal walls 15 and 17 , of which the wall 15 is at a small distance V from the free sector of the guide rollers 34 , 35 and 44 . The walls 14 and 15 are stiffened by pipe sections 11 a and 12 a , which extend over the entire width of the blow box 10 . To the pipe sections 11 a and 12 a befin the after FIGS. 3 and 5 Coandadüsen 11 and 12, the common sam of the pipe sections 11 a and 12 a and plate pieces or the bending edges of the walls are limited 14 and 15. The opposite vertical end faces of the blow box 10 are closed by walls 21 ( Fig. 2). On one or both end faces 21 there are air channels 22 through which blown air and possible pocket ventilation air are brought into the box 10 . The pressure p of the blown air is suitably approx. P = 1000 ... 1500 Pa.

The Coanda nozzles 11 and 12 are aligned in such a way that an air jet F 1 can be directed along the sieve 30 in the opposite direction to its direction of travel through the nozzle 11 located in the vicinity of the drying wire 30 , 40 . By the near the guide roller 34 , 45 located second nozzle gap 12 , an air jet F 2, the guide roller 34 , 35 , 44 tan ging in the opposite direction to the direction of movement are directed.

It is essentially new in the invention that air jets F 1 are expressly blown out of the first Coanda nozzle 11 in the opposite direction to the entry direction of the screen 30 , 40 through an elongated passage R. The length L of said passage R is in the range L = 100-500 mm, expediently in the range L = 250-350 mm. The width M of the passage, ie the distance between the arcuate wall 14 of the box 10 and the opposite sieve 30 , 40 is generally in the range M = 20-100 mm, expediently in the range M = 40-70 mm, for example approx. 50 mm, which is the generally required safety distance that can be used advantageously according to the invention. The length L of the passage mentioned is a multiple, generally 3 to 10 times, suitably 5 to 7 times the width M of the passage, ie L / M = 3-10, suitably L / M = 5-7. By this dimensioning, it is firstly ensured that air is effectively ejected from the vacuum space A- and N- and secondly that the boundary layer flow following the outer surface of the sieve 30 , 40 is essentially completely destroyed and in the direction of the flow F 1 is reversed.

With the air jets F ₁ and F ₂ mentioned air from the space A- between the dryer fabric 30 and the wall 14 of the blow box 10 and the wedge-shaped space between the Troc kensieb 30 , 40 and the guide roller 34 , 45 in the direction of the arrows E ₁ and E ₂ ejects in such a way that sufficient negative pressure is created in said rooms. With the aforementioned negative pressure, which can be of the order of up to 100 Pa, the effect is achieved that the web W, after detachment from the surface of the cylinder 31 , 41, effectively sticks to the drying wire 30 , 40 , which is relatively permeable to air is. The web W remains on the surface of the screen until the gap N- ends, ie up to the line at which the drying screen 30 , 40 touches the guide roller 34 , 44 . The said tanging point is located on or in the vicinity of a horizontal plane through the center point of the guide roller 34 , 44 . After detachment from the tanging point, the web runs on to the next drying cylinder essentially as a free train Wp after detachment from the transport screen 30 , 40 .

The width of the nozzle gaps 15 and 16 is generally s = 2-5 mm. The speed of the air jets F 1 and F ₂ in the nozzle columns 11 and 12 is generally in the range v = 15-50 m / s.

In the following the special features and common differences of the individual embodiments shown in FIGS. 3 to 6 are explained. In the blow box of Fig. 3 and 4 also pocket ventilation is applied, which means that kenzylinder on withdrawal of the wire between the guide roll 34, 44 and Troc 32, 42 a pressure range S + is set up, one with the on withdrawal of the wire 30, 40 Flow F in the pocket T is reached to ventilate it. According to Fig. 2, flows F 3 in the central region of web W are introduced because the edge regions of web W naturally endeavor to dry out more.

Said overpressure area S +, which is expediently arranged in the central area of the web W in order to increase its ventilation, is generated with the aid of a nozzle 13 arranged on the outer wall of the blow box 10 and connected to an air duct 18 . Through the nozzle 13 are shown in FIG. 2, 3 and 4 blowings F 3 with respect to the direction of movement of the wire 30 is blown in the opposite direction 40 so that in the gap between the straight train of the wire 30, 40 and the wall 16 of the box 10 as well as in the exit gap between the screen and the guide roller of the pressure range S + is formed which is expanded in FIG. 3 or by the second erzeug through nozzle 12 th blowings F2.

According to Fig. 4, no second blow nozzle 12 is used, but it is processing by a secured to the sleeve 19 like replaced 20 against the outer surface of the guide roller 34, 35, loops 44 and both seals as well as the negative pressure region A, N- separates from the overpressure area S +. According to FIG. 4, no ejection flow E 2 is generated by the gap space V , as is the case in FIG. 3.

FIG. 2 shows a blow box according to FIGS . 3 and 4 viewed from direction B shown in FIG. 1. The blower box 10 consists of pocket ventilation from a 13 13-1 13 N segmented blowing nozzle 13 , from which adjustable currents F 31 ... F 3 N are directed into the gap space S +. In the nozzle segments 13: 1 - 13 N flows are in Seg elements by a 26 1 -26 N divided channel 18 out. In the channel segments 26 1 -26 N are control valves 25 1 - 25 N, with which the amount of by the nozzle segments 13: 1 - 13 N court ended blowings F ... 31 F 3 N is controlled. In the segments 26: 1 - 26 N of the channel 18 is a one occurs in flow F 1 brought by a channel 22nd Accordingly, the blows introduced through the nozzles 11 and 12 or only through the nozzle 11 are supplied through an opposite channel 23 as the blowing F in FIG. The supply air F in 1 of the pocket ventilation is hot and dry, whereas moist air can also be used as the blowing F 1 . The air supplied through the second nozzle 12 is expediently dry air because it gets into the pocket T in order to ventilate it.

As can be seen from FIG. 1, the screen 40 and the free train W p of the web W come separately into the inlet gap N + of the cylinder 42 .

In connection with the method and the device of the invention it is advantageous to use substantially more permeable sieves 30, 40 , the permeability of which is advantageous instead of normal two sieve guide drying sieves, the permeability of which is in the range 1500-2000 m 3 / m 2 × h Be rich 5000 m 3 / hm 2 -20 000 m 3 / m 2 h, suitably in the range 10 000-15 000 m 3 / hm 2 × h.

In Fig. 3 to 6 are some advantageous execution forms of the invention is shown. The mutual relationships of the gap spaces are tried in Fig. 3-6 to represent as correctly as possible. The size of the nozzle column 11 , 12 and 13 is to some extent exaggerated for the sake of clarity. In order to create a basis for comparison for the dimensions of the individual elements shown in the figures, a design example is given below. The diameter of the drying cylinder 31 , 32 , 41 , 42 is 1830 mm, the common distance between the horizontal axes through the central axes of the drying cylinder is 200 mm, the division in the horizontal direction of the cylinders of the top and bottom row is 2600 mm and the diameter of the Guide rollers 700 mm. However, this example is not intended to limit the scope of the invention in any way.

In a manner known per se, paper machines in the first cylinder groups of the dryer section single-wire guide and in the latter groups, e.g. in the 3rd-4th Group, two sieve guidance applied. The method and the device of Invention are in one or more two-wire guide groups either in one or more cylinders between clearing applied. The invention is advantageously used e.g. in one or two first two-wire guides in the direction of travel of the web groups in which the railways, due to their Moisture levels because of their firmness and their ela properties sensitive to flutter and tearing is.

Claims (11)

1. Method in a paper machine cylinder dryer, in which the web is guided using an upper wire ( 40 ) on the upper cylinders and a lower wire ( 30 ) on the lower cylinder, the screens ( 30 , 40 ) from the surface of the drying cylinders and in the spaces arranged guide rollers ( 34 , 35 , 44 ) are guided such that the web ( W ) on the top cylinder row by pressing the top wire ( 40 ) has direct drying contact with the surface of the top cylinder ( 41 , 42 ) and accordingly from the bottom wire ( 30 ) is pressed against the surface of the lower cylinder ( 31 , 32 ), and the web ( W ) in the process from one to the other cylinder row on a certain route in free train ( W p ), and the web ( W ) in this method, while the web (W) and drying (30, 40), the drying cylinder (31, leaving sen 41) under Durchsaugung of the drying wire (30, 40) in a relevant at the location of Trockensiebzuges arranged vacuum area (A-, N-) is sucked firmly onto the dryer fabric ( 30 , 40 ) in such a way that the length of the free train ( W p ) of the web is significantly shortened, and the suction effect by Bla solution of at least one or more the running direction of the dryer fabric ( 30 , 40 ) located at this point in the opposite direction air jet or air jets ( F 1 ; F 1 , F 2 ) is obtained, which eject from the rooms (A-, N-) lying behind (E ₁; E ₁, E ₂), whereby the vacuum range mentioned is generated, characterized in that the said negative pressure region (A-, N-) is generated with a blow, which is delimited in a blow by a screen ( 30 , 40 ) located on the drying cylinder ( 31 , 32 , 41 , 42 ) and a wall surface ( 14 ) directional elongated (L) passage ( R ) is blown, and that with the said sufficiently long passage ( R ) the Troc kensieb ( 30 , 40 ) following boundary layer flow essentially as a whole with respect to the train of sieve ( 30 , 40 ) oppositely directed is and a sufficient vacuum level is isolated in the rooms at the rear of the named passage ( R ).
2. The method according to claim 1, characterized in that the speed ( v ) of said blow ( F 1 ) and the dimensions ( L , M ) of said passage ( R ) are chosen such that in the joint of the rear passage ( R ) located sieve ( 30 , 40 ), on the opposite side due to the negative pressure, the web ( W ) tet, and the wire guide roller ( 30 ) and the wall ( 14 ) of the blower box ( 10 ) creates limited spaces , which is in the order of 75-150 Pa, suitably about 100 Pa.
3. The method according to claim 1 and 2, characterized in that in the method a second nozzle ( 12 ) is used, through which in the free sector of the guide roller ( 34 , 35 , 44 ) from the wall ( 15 ) of Blow box ( 10 ) limited gap space ( V ) second air jets ( F 2 ) are blown, with which air is ejected from said gap (N-) between the screen ( 30 , 40 ) and its guide roller ( 34 , 35 , 44 ) ( Fig. 1, 3, 5).
4. The method according to claim 1 to 3, characterized in that with the method, an overpressure area (S +) is applied, in the course of the screen ( 30 , 40 ) from its guide roller ( 34 , 35 , 44 ) to the drying cylinder on Web ( W ) is established, and the overpressure area (S +) with Blasun gene ( F 3 ) is generated by a in the walls ( 16 , 17 ) of the box ( 10 ) located blowing nozzle ( 13 ) in the gap between the Wall ( 16 ) of the blow box ( 10 ) and the said train of the sieve ( 30 , 40 ) are directed.
5. The method according to claim 4, characterized in that on the said blowing nozzles ( 13 ) segment control ( 1 - N) is applied, with which the transverse to the web ( W ) moisture profile is controlled.
6.Device for a paper machine multi-cylinder dryer, in which two-sheet guiding is used, and the device is intended to be arranged in the interspaces next to each other drying cylinders, the interstices of the drying cylinders ( 30 , 40 ) running over the adjacent drying cylinders and the free sectors of these leading guide rollers ( 34 , 35 , 44 ) are limited, the device consisting of a blow box ( 10 ) be, which extends over the entire width of the dryer fabric ( 30 , 40 ), and the blow box ( 10 ) at least has a nozzle gap ( 11 ) which is arranged and aligned in such a way that from the said nozzle gap ( 11 ) a blow ( F 1 ) with respect to the direction of movement of the drying sieve passing at this point ( 30 , 40 ) is directed in the opposite direction lets, characterized in that behind the nozzle ( 11 ), expediently Coanda nozzle ( 11 ), in their blowing direction ( F 1 ) behind d he nozzle is attached to a wall ( 14 ) of the blow box ( 10 ) which, together with the outer surface of the sieve ( 30 , 40 ) located on the drying cylinder surface in the region of the wall, delimits an elongated passage ( R ), the length ( L ) of which is a multiple is greater than the width ( M ) of the passage, ie as the distance from the outer surface of the sieve ( 30, 40 ) to said wall surface ( 14 ) of the blow box ( 10 ).
7. The device according to claim 6, characterized in that the length of said passage ( R) L = 100-500 mm, suitably L = 250-350 mm, and that the width of said passage M = 20-100 mm, expediently M = 40-70 mm, and that the ratio of the length ( L ) of said passage to its width ( M ) L / M = 3-10, expediently L / M = 5-7.
8. Apparatus according to claim 6 and 7, characterized in that the said blow box ( 10 ) has a second nozzle, advantageously Coanda nozzle ( 12 ), which is located on that wall ( 15 ) of the blow box ( 10 ) with a small Distance ( V ) to the free sector of the wire deflecting roller ( 34 , 35 , 44 ), and that said second nozzle ( 12 ) is arranged and aligned in such a way that from it a second blow ( F ₂) in the opposite direction to Direction of movement of the guide roller surface ( 34 , 35 , 44 ) located at this point can be blown (FIGS . 1, 3, 5).
9. Apparatus according to claim 6 and 7, characterized in that in the vicinity of the free sector of the Siebleit roller ( 34 , 35 , 44 ) of the blow box ( 10 ) is a sealing arrangement ( 19 , 20 ) which on the entry side of the drying wire (30, 40) located vacuum chamber (a, N) of the on the outlet side of the drying wire (30, 40) via pressure chamber located (S +) is separated (Fig. 4 and 6).
10. The device according to claim 6 to 9, characterized in that the blow box ( 10 ) has a mainly flat wall ( 16 ) which is arranged at a short distance from the train of the drying sieve ( 30 , 40 ), as which the screen of be ner guide roller ( 34 , 35 , 44 ) runs to the drying cylinder on the web (W) , and that there is a third nozzle, expedient Coanda nozzle ( 13 ) on the outer part of said wall, from which a third blow ( F 3 ) in the Space between said wall ( 16 ) and the train of the dryer fabric ( 30 , 40 ) located in their vicinity can be directed to produce the overpressure area (S +) ( Fig. 1, 3 and 4).
11. The device according to claim 10, characterized in that said third blow ( F 3 ) with a feed channel ( 18 ) for the dry air of the segment-controlled ( 1 - N) pocket ventilation is connected, with which segment the moisture profile control in the transverse direction web ( W ) to be dried is mastered ( FIG. 2).
DE19883818600 1987-06-17 1988-06-01 Expired - Lifetime DE3818600C2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FI872691A FI80103C (en) 1987-06-17 1987-06-17 Method and apparatus in the cylinder dryer of a paper machine, in which a double-weave pull is used

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DE3818600A1 true DE3818600A1 (en) 1988-12-29
DE3818600C2 DE3818600C2 (en) 1991-09-19

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SE (1) SE467626B (en)

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DE3831280A1 (en) * 1987-09-29 1989-04-06 Valmet Paper Machinery Inc Method and device in a paper machine cylinder dryer
WO1990004065A1 (en) * 1988-10-11 1990-04-19 Beloit Corporation A dryer section apparatus
DE3914761A1 (en) * 1989-03-08 1990-11-15 Voith Gmbh J M Guide roller for a porous band, for example for a dry screen of a paper machine
EP0566552A1 (en) * 1992-04-10 1993-10-20 Valmet Corporation Device for stabilization of the paper web in a group of cylinders in the drying section of a paper machine
DE4404726A1 (en) * 1993-03-11 1994-09-15 Voith Gmbh J M Twin-wire cylinder dryer
EP0620314A2 (en) * 1993-04-05 1994-10-19 Valmet Paper Machinery Inc. Method for ventilation of the pocket spaces in a multi-cylinder dryer of a paper machine and apparatus for ventilation of a pocket space in a multi-cylinder dryer of a paper machine
US5477624A (en) * 1993-03-11 1995-12-26 J. M. Voith Gmbh Two-wire cylinder dryer
EP0726353A2 (en) 1995-02-01 1996-08-14 Valmet Corporation Method for producing surface-treated paper and dry end of a paper machine
DE19527289A1 (en) * 1995-07-26 1997-01-30 Voith Sulzer Papiermasch Gmbh Method and device for drying a fibrous web
US5840101A (en) * 1995-05-27 1998-11-24 Wet Tex Maschinenbau Gmbh Method and apparatus for treatment of an endless web of material with vacuum
US6076280A (en) * 1995-07-26 2000-06-20 Voith Sulzer Papiermaschinen Gmbh Method and device for drying a fiber web

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JPH06185142A (en) * 1992-12-16 1994-07-05 Sekisui Chem Co Ltd Wall panel connecting structure
FI93875C (en) * 1994-02-17 1995-06-12 Valmet Paper Machinery Inc Procedure for drying a paper web and drying part in a paper machine
US5661911A (en) * 1994-02-17 1997-09-02 Valmet Corporation Dryer section of a paper machine
CA2190563C (en) * 1996-11-18 1999-10-26 Ralph Mancini Device and method to stabilize sheet between press section and dryer section of a paper-making machine
US6260287B1 (en) 1997-08-08 2001-07-17 Raffaele Mancini Wet web stability method and apparatus
FI20022231A0 (en) 2002-12-19 2002-12-19 Metso Paper Inc Arrangement for tissue stabilization of the web

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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3831280A1 (en) * 1987-09-29 1989-04-06 Valmet Paper Machinery Inc Method and device in a paper machine cylinder dryer
WO1990004065A1 (en) * 1988-10-11 1990-04-19 Beloit Corporation A dryer section apparatus
DE3914761A1 (en) * 1989-03-08 1990-11-15 Voith Gmbh J M Guide roller for a porous band, for example for a dry screen of a paper machine
EP0566552A1 (en) * 1992-04-10 1993-10-20 Valmet Corporation Device for stabilization of the paper web in a group of cylinders in the drying section of a paper machine
US5509215A (en) * 1992-04-10 1996-04-23 Valmet Paper Machinery Inc. Method and device for stabilization of a paper web in a group of cylinders in a drying section of a paper machine
DE4404726A1 (en) * 1993-03-11 1994-09-15 Voith Gmbh J M Twin-wire cylinder dryer
US5477624A (en) * 1993-03-11 1995-12-26 J. M. Voith Gmbh Two-wire cylinder dryer
EP0620314A3 (en) * 1993-04-05 1994-11-23 Valmet Paper Machinery Inc Method for ventilation of the pocket spaces in a multi-cylinder dryer of a paper machine and apparatus for ventilation of a pocket space in a multi-cylinder dryer of a paper machine.
EP0620314A2 (en) * 1993-04-05 1994-10-19 Valmet Paper Machinery Inc. Method for ventilation of the pocket spaces in a multi-cylinder dryer of a paper machine and apparatus for ventilation of a pocket space in a multi-cylinder dryer of a paper machine
EP0726353A2 (en) 1995-02-01 1996-08-14 Valmet Corporation Method for producing surface-treated paper and dry end of a paper machine
EP0916763A2 (en) 1995-02-01 1999-05-19 Valmet Corporation Method for producing surface-treated paper and dry end of a paper machine
US5840101A (en) * 1995-05-27 1998-11-24 Wet Tex Maschinenbau Gmbh Method and apparatus for treatment of an endless web of material with vacuum
DE19527289A1 (en) * 1995-07-26 1997-01-30 Voith Sulzer Papiermasch Gmbh Method and device for drying a fibrous web
US6076280A (en) * 1995-07-26 2000-06-20 Voith Sulzer Papiermaschinen Gmbh Method and device for drying a fiber web
DE19527289C2 (en) * 1995-07-26 2000-09-14 Voith Sulzer Papiertech Patent Pocket ventilation method and an air guide box for performing the method in a two-wire dryer section of a papermaking machine

Also Published As

Publication number Publication date
FI80103C (en) 1990-04-10
JP2631226B2 (en) 1997-07-16
JPS6414392A (en) 1989-01-18
DE3818600C2 (en) 1991-09-19
SE8801979D0 (en) 1988-05-27
FI872691A0 (en) 1987-06-17
FI80103B (en) 1989-12-29
SE8801979L (en) 1988-12-18
SE467626B (en) 1992-08-17
FI872691A (en) 1988-12-18
CA1336535C (en) 1995-08-08
FI872691D0 (en)

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Owner name: VALMET CORP., HELSINKI, FI